Lead author Pavel Goldstein, a postdoctoral pain researcher in the Cognitive and Affective Neuroscience Lab at CU Boulder says, “this paper illustrates the power and importance of human touch.” The study was published in 2018 in the journal Proceedings of the National Academy of Sciences (PNAS), by researchers with the University of Colorado Boulder and University of Haifa. The researchers found that the more empathy a comforting partner feels for a partner in pain, the more their brainwaves fall into sync. And the more those brain waves are in sync, the more the pain goes away.
The study is the latest in a growing body of research exploring a phenomenon known as “interpersonal synchronization,” in which people physiologically mirror the people they are with. It is the first to look at brain wave synchronization in the context of pain, and offers new insight into the role brain-to-brain coupling may play in touch-induced analgesia, or healing human touch.
How exactly could coupling of brain activity with an empathetic partner kill pain? In an experiment conducted with 22 heterosexual couples, an electroencephalography (EEG) machine measured brainwave signals from both partners simultaneously as the couples were put into various scenarios. The scenarios included sitting together not touching; sitting together holding hands; and sitting in separate rooms. The scenarios were again repeated as the woman was subjected to mild heat pain on her arm.
The Results of Holding Hands
It seems that being in each other’s presence, with or without touch, was associated with some brain wave synchronicity in the alpha mu band, a wavelength associated with focused attention. Researchers also found that when she was in pain and he couldn’t touch her, the coupling of their brain waves diminished, while heart rate and respiratory synchronization disappeared. If the couples held hands while she was in pain, the coupling increased the most. Subsequent testing revealed the more synchronized their brains, the more her pain subsided. “It appears that pain totally interrupts this interpersonal synchronization between couples and touch brings it back,” says Goldstein.
Why holding hands while one partner was in pain caused the two people’s brain waves to synchronize, with cells firing in the same pattern in the same location is not quite known. But Goldstein and his co-authors offered an explanation. Empathetic touch makes a person feel understood, which in turn, activates pain-killing mechanisms in the brain.
More studies on interpersonal synchronization are needed to find out exactly how coupling of brain activity with an empathetic partner can lessen pain. But the takeaway for now is to not underestimate the power of holding a loved one’s hand.